Parents need to raise their boys to become good husbands, otherwise, more and more men will join the 80%.
Girls from birth almost, are raised to be caring, emotionally intelligent and of course, trained how to look and act 'attractive'. Meanwhile boys are ruined from early on, taught not to express themselves emotionally which means they struggle to form meaningful connections beyond their family. Then you have the patriarchal families who don't even train their boys to do basic household chores. So, what do you end up with? An emotionally repressed, lazy or incapable adult male. This is not an attractive person. Since women are no longer dependent on men for sustenance, fewer and fewer women are settling for these males.
A lot of women are not afraid to be alone, because they have social support. Men, don't tend to have as much social support, because again, this was not conditioned into them. This is why they become angry shut-ins who turn to the internet for community; because we are not designed to be alone.